Another turbine which has come into extensive use is the " Francis," an exceedingly efficient turbine on a low fall with large quantities" of water.
Tests of a turbine of this slow-moving type showed an efficiency of 82% at full gate, and one of 75% when half of the passages in the guide-blades were closed by the shutters, as described above.
In July 1888 the Societe Metallurgique Suisse erected plant driven by a 500 h.p. turbine to carry out Heroult's alloy process, and at the end of that year the Allgemeine Elektricitais Gesellschaft united with the Swiss firm in organizing the Aluminium Industrie Actien Gesellschaft of Neuhasen, which has factories in Switzerland, Germany and Austria.
Efficiency of the Francis turbine being in this case 86% at full load and 77% at half load.
At 150 revolutions, each turbine will have a nominal horsepower of woo.
Another turbine of the mixed flow type is the " Victor," which consists of three parts - the outer guide case, and, inside this, the register gate, and the wheel.
In the " Hercules " turbine, shown in fig.
This difficulty may be overcome by using Rateau's arrangement of a low-pressure turbine between the engine and the condenser.
2 The following statistics of turbine construction in Switzerland are taken from Schweizerische Bauzeitung (1901), p. 128, which, in the same volume at p. 53, contains a valuable article on the most important improvements in turbines and their regulation shown in the Paris Exhibition of 1901: - of one of these, which gave an efficiency of 87% at full load and 70% at about three-fifths full load.